1. Field of the Invention
The present invention relates to a method of hydrogenating epoxidized C6-C12 cyclohydrocarbon compounds. More particularly, the present invention relates to a method of hydrogenating epoxidized C6-C12 cyclohydrocarbon compounds, to produce, for example, C6-C12 cycloalkanols and/or C6-C12 cycloalkanones. The C6-C12 cycloalkanols, for example, cyclododecanol and the C6-C12 cycloalkanones, for example, cyclododecanone, are useful as intermediate compounds for producing lactams, lactones and polycarboxylic acids, which are useful for polyamides and polyesters for synthetic resins and synthetic fibers.
2. Description of the Related Art
It is known that a mixture of a cycloalkanone with a cycloalkanol can be produced by oxidizing a cycloalkane with air in the presence of a catalyst comprising boric acid. In this method, the air oxidation is effected in successive reactions and thus a plurality of by-products are produced during the reactions. Thus, the conversion of the cycloalkane must be low and the yield of the target mixture of cycloalkanol with cycloalkanone is usually low. For example, in the air oxidation of cyclododecane in the presence of a boric acid catalyst, it is known that the mixture of cyclododecanone with cyclododecanol is obtained in a yield of 20 to 25%. Also, it is known that when cyclohexane is oxidized with air, the yield of the mixture of cyclohexanone with cyclohexanol is several %.
Also, it is known that epoxidized cycloalkanes and/or epoxidized cycloalkenes can be produced by epoxidizing corresponding cycloalkenes with a high yield. If the epoxidized compounds can be converted to corresponding cycloalkanones and cycloalkanols with a high efficiency, the cycloalkanones and the cycloalkanols can be expected to be obtained at a high yield. However, only a small number of reports can be found on methods of converting an epoxidized cycloalkane and/or an epoxidized cycloalkene to a mixture of cycloalkanone with cycloalkanol. For example, J. Mol. Catal., Vol. 69, pages 69 to 103 (1991) discloses a method of hydrogenating a monoepoxycyclododecadiene with hydrogen in the presence of a catalyst comprising palladium carried on a carrier consisting of xcex3-alumina, under a hydrogen gas pressure of 1.3 MPa at a temperature of 90xc2x0 C. In this method, cyclododecanol was produced with a yield of 20% or less and no cyclododecanone was produced. When a catalyst comprising palladium carried on a carrier consisting of titania or silica was used in place of the above-mentioned palladium catalyst carried on xcex3-alumina, the yield of cyclododecanol was low and unsatisfactory.
Also, the Drafted Report of 24th Symposium of Development in Reaction and Synthesis, Nov. 5 to 6, 1998, page 68, discloses a method of hydrogenating 1,2-epoxy-5,9-cyclododecadiene with hydrogen at ambient atmospheric pressure and room temperature in the presence of a catalyst comprising palladium carried on a carrier consisting of a carbon material. In this method, cyclododecanol was produced with a yield of 5% and no cyclododecanone was obtained.
Further, Neftekhimiya, 16(1), 119xe2x80x94119, (1976) discloses a method in which 1,2-epoxy-5,9-cyclododecadiene is brought into contact with hydrogen in the presence of a palladium-carrying catalyst under a hydrogen pressure of 9.06 MPa (80 atmospheres) at a temperature of 140xc2x0 C. By this method, 49.5% of epoxycyclododecane, 33.3% of cyclododecanol and 3.4% of cyclododecanone were obtained. In this method, the yields of cyclododecanol and cyclododecanone were unsatisfactory.
As mentioned above, when the 1,2-epoxy-5,9-cyclododecadiene is hydrogenated with a hydrogen gas by the known methods, the yields of cyclododecanol and cyclododecanone are very low and unsatisfactory.
As an analogous method, Synthetic Communication, 25(15), pages 2267 to 2273 (1995) discloses a method of synthesizing cyclohexanol by hydrogenating 1,2-epoxy-5,9-cyclohexane. In this method, 1,2-epoxy-5,9-cyclohexane was reduced with ammonium formate (HCOONH4) in the presence of a catalyst comprising palladium carried on a carrier consisting of activated carbon, and as a result, cyclohexanol was produced with a yield of 50% and no cyclohexanone was obtained. This method is, however, disadvantageous in that the ammonium formate (HCOONH4) which is used as a hydrogen-supply source, is expensive, and the yields of cyclohexanol and cyclohexanone are low although the expensive hydrogen-supply source is employed. Therefore, this method is practically unusable as a production method of cycloalkanone and cycloalkanol which are useful for producing lactam materials.
Accordingly, no method of producing C6-C12 cycloalkanols and C4-C12 cycloalkanones with a satisfactory yield, from epoxidized C6-C12 cyclohydrocarbon compounds, for example, C6-C12 cycloalkanes cycloalkadienes and/or cycloalkenes, has been known.
An object of the present invention is to provide a method of hydrogenating epoxidized C6-C12 cyclohydrocarbon compounds in the presence of a platinum group metal-containing catalyst with a high efficiency.
Another object of the present invention is to provide a method of hydrogenating epoxidized C6-C12 cyclohydrocarbon compounds in the presence of a platinum group metal-containing catalyst in one single-step reaction with a high yield of hydrogenated cyclohydrocarbon compounds.
The above-mentioned objects can be attained by the method of the present invention.
The method of the present invention for hydrogenating epoxidized C6-C12 cyclohydrocarbon compounds, comprising bringing a starting material comprising at least one epoxidized cyclohydrocarbon compound having 6 to 12 carbon atoms into contact with hydrogen under a hydrogen pressure of 0.1 to 5.4 MPa on gauge at a temperature of 100 to 280xc2x0 C. in the presence of a catalyst comprising a catalytic metal component comprising at least one platinum group metal.
In the hydrogenating method of the present invention, the starting material may comprise at least one member selected from the group consisting of monoepoxy C6-C12 cycloalkenes, monoepoxy C6-C12 cycloalkanes and monoepoxy C6-C12 cycloalkadiens and the resultant hydrogenation reaction product may comprise at least one member of C6-C12 cycloalkanones and C6-C12 cycloalkanols.
In the hydrogenating method of the present invention, the catalytic metal component of the catalyst is optionally carried on an inert carrier comprising at least one member selected from the group consisting of activated carbon, alumina, silica, silica-alumina, titania, zeolites and spinel, especially xcex1-alumina.
In an embodiment of the hydrogenating method of the present invention, the starting material comprises at least one member selected from the group consisting of monoepoxy cyclododecanes, monoepoxy cyclododecenes and monoepoxy cyclododecadienes, and is brought into contact with hydrogen under a hydrogen pressure of 0.1 to 5.4 MPa on gauge at a temperature of 100 to 280xc2x0 C., in the presence of a catalyst comprising, as a catalytic metal component, at least one metal selected from the group consisting of palladium and ruthenim, to produce cyclododecanol and cyclododecanone.
In another embodiment of the hydrogenating method of the present invention, the starting material comprises 1,2-epoxy-5,9-cyclododecadiene and is brought into contact with hydrogen under a hydrogen pressure of 0.1 to 3.9 MPa on gauge at a temperature of 100 to 280xc2x0 C., in the presence of a catalyst comprising, as a catalytic metal component, at least one platinum group metal, to produce cyclododecanone.
In still another embodiment of the hydrogenating method of the present invention, the catalytic metal component of the catalyst is carried on an inert carrier comprising a-alumina, and the starting material is hydrogenated into a mixture of C6-C12 cycloalkanone with C6-C12 cycloalkanol.
In the method of the present invention, hydrogenating epoxidized C6-C12 cyclohydrocarbon compounds are hydrogenated by bringing a starting material comprising at least one epoxidized cyclohydrocarbon compound having 6 to 12 carbon atoms into contact with hydrogen under a hydrogen pressure of 0.1 to 5.4 MPa on gauge at a temperature of 100 to 280xc2x0 C. in the presence of platinum group metal-containing catalyst.
The starting material for the method of the present invention comprises at least one member selected from epoxidized cyclohydrocarbon compounds having 6 to 12 carbon atoms, which compounds may be saturated or unsaturated.
The epoxidized C6-C12 cyclohydrocarbon compounds are preferably selected from monoepoxy C6-C12 cycloalkanes, monoepoxy C6-C12 cycloalkenes and monoepoxy C6-C12 cycloalkadienes. The epoxidized C6-C12 cyclohydrocarbon compounds may have two or more epoxy groups.
In the method of the present invention, the hydrogenation reaction product comprises at least one member selected from the group consisting of C6-C12 cycloalkanols and C6-C12 cycloalkanones, corresponding to the starting epoxidized C6-C12 cyclohydrocarbon compound.
The epoxidized C6-C12 cycloalkanes include epoxidized cyclohexanes, epoxidized cycloheptanes, epoxidized cyclooctanes, epoxidized cyclononanes, epoxidized cyclodecanes, epoxidized cycloundecanes and epoxidized cyclododecanes.
The epoxidized C6-C12 cycloalkenes include epoxidized cyclohexenes, epoxidized cycloheptenes, epoxidized cyclooctenes, epoxidized cyclononenes, epoxidized cyclodecenes, epoxidized cycloundecenes and epoxidized cyclododecenes.
The epoxidized C6-C12 cycloalkadienes include epoxidized cyclohexadienes, epoxidized cycloheptadienes, epoxidized cyclooctadienes, epoxidized cyclononadienes, epoxidized cyclodecadienes, epoxidized cycloundecadienes, and epoxidized cyclododecadienes, which may be in cis-, trans- and other structures.
In the method of the present invention, the resultant C6-C12 cycloalkanols include cyclohexanol, cycloheptanol, cyclooctanol, cyclononanol, cyclodecanol, cycloundecanol and cyclododecanol. Also, the cycloalkanones include cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone, cyclodecanone, cycloundecanone and cyclododecanone.
In the method of the present invention, the starting material may contain impurities, for example, non-epoxidized cyclohydrocarbon compounds, for example, cycloalkanes, cycloalkanols and cyclalkanones. In the method of the present invention, the platinum group metal-containing catalyst is in the state of a solid and comprises, as a catalytic metal component, at least one member selected from ruthenium, rhodium, palladium, osmium, iridium and platinum, preferably ruthenium and palladium, more preferably palladium.
The platinum group metal-containing catalyst optionally contains an inert carrier on which the catalytic metal component is carried. The inert carrier preferably comprises at least one member selected from the group consisting of activated carbon, alumina, silica, silica-alumina, zeolite and spinel.
The solid platinum group metal-containing catalyst is preferably in the form of fine particles, having an average particle size of 1 to 1000 xcexcm, more preferably 10 to 100 xcexcm, or in the form of pellets having an average length of 1 to 10 mm and an average diameter of 2 to 6 mm. In the catalyst having the inert carrier, the catalytic metal component is preferably in an amount of 0.1 to 20% by weight, more preferably 0.5 to 10% by weight, based on the weight of the inert carrier.
In the catalyst for the hydrogenating method of the present invention, the catalytic metal component may be located on the surface or in the inside or both on the surface and in the inside, of the inert carrier.
In the hydrogenating method of the present invention, the catalyst is preferably employed in an amount of 0.00001 to 0.1 mole, more preferably 0.00005 to 0.01 mole, in terms of the total platinum group metal atoms, per mole of the starting material.
In the hydrogenating method of the present invention, the catalytic reaction of the starting material with hydrogen may be effected in an organic liquid reaction medium which is non-reactive with hydrogen and the starting material under the reaction conditions. The liquid medium preferably comprises at least one member selected from, liquid hydrocarbons, for example, n-hexane, n-heptane, n-tetradecane and cyclohexane; liquid ethers, for example, tetrahydrofuran and dioxane; liquid alkanols, for example, methyl alcohol, ethyl alcohol and t-butyl alcohol and t-aryl alcohol; liquid esters, for example, ethyl acetate and butyl acetate. These liquid compounds may be employed alone or in a mixture of two or more thereof. The liquid medium is preferably used in an amount of 20 times or less, more preferably 10 times or less, the weight of the starting material.
The liquid medium may make control of the reaction easy.
In the hydrogenating method of the present invention, the starting material is introduced into a reactor and is brought into contact with a hydrogen gas introduced into the reactor under a hydrogen pressure of 0.1 to 5.4 MPa on gauge, preferably 0.2 to 5.4 MPa on gauge, more preferably 0.2 to 3.9 MPa on gauge, at a temperature of 100 to 280xc2x0 C., preferably 100 to 230xc2x0 C., more preferably 120 to 200xc2x0 C., in the presence of the platinum group metal-containing catalyst.
When the hydrogen pressure is less than 0.1 MPa on gauge, the reaction time necessary to complete the hydrogenating reaction becomes too long and thus is practically disadvantageous. When the hydrogen pressure is more than 5.4 MPa on gauge, the target product is obtained with too low a yield.
When the reaction temperature is less than 100xc2x0 C., the yield of the target product is unsatisfactory, and when the reaction temperature is more than 280xc2x0 C., undesired side reactions occur to cause undesired by-products to be produced.
There is no limitation to the type of reactor for the hydrogenating reaction. The reaction can be carried out in a liquid phase, catalyst-suspension bed type reactor or a catalyst-fixed bed type reactor. In the catalyst suspension bed type reactor, the catalyst in the form of fine particles is used. Also, in the catalyst-fixed bed type reactor, the catalyst in the form of pellets in employed. In the catalyst-fixed bed type reactor, the hydrogenation of the starting material may be effected by a trickle reaction, a liquid phase reaction or a gas phase reaction.
After the hydrogenation reaction is completed, the reaction product-containing mixture is subjected to a procedure for collecting and refining the target product by, for example, distillation and crystallization.
In an embodiment (1) of the method of the present invention, a starting material comprising at least one monoepoxy C12 cyclohydrocarbon compound selected from monoepoxy saturated and unsaturated C12 cyclohydrocarbon compounds, for example, monoepoxy cyclododecane, monoepoxy cyclododecene and monoepoxy cyclododecadiene, is brought into contact with hydrogen in the presence of a catalyst comprising, as a catalytic metal component, at least one member selected from platinum group metals, preferably palladium and ruthenium, under a hydrogen pressure of 0.1 to 5.4 MPa on gauge, preferably 0.5 to 5.4 MPa on gauge and more preferably 1.0 to 5.4 MPa on gauge at a temperature of 100 to 280xc2x0 C., preferably 120 to 230xc2x0 C., more preferably 120 to 200xc2x0 C. to produce cyclododecanol and cyclododecanone. In this embodiment (1), the catalyst preferably has an inert carrier on which the catalytic metal component is carried. The carrier preferably comprises at least one member selected from activated carbon, aluminum, silica, zeolite and spinel, and the catalytic metal component (palladium or ruthenium) are carried, in an amount of 1 to 20% by weight, on the surface and/or in the inside of the carrier.
The hydrogenation reaction may be carried out in the liquid reaction medium as mentioned above.
In another embodiment (2) of the method of the present invention, 1,2-epoxy-5,9-cyclododecadiene, which may be in cis- or trans type, is brought into contact with hydrogen in the presence of a catalyst comprising, as a catalytic metal component, at least one platinum group metal under a hydrogen pressure of 0.1 to 3.9 MPa on gauge preferably 0.2 to 3.9 MPa on gauge, more preferably 0.2 to 2.9 MPa on gauge at a temperature of 100 to 280xc2x0 C., preferably 100 to 230xc2x0 C., more preferably 120 to 200xc2x0 C., to produce cyclododecanone. In this embodiment, the catalytic metal component of the catalyst comprises palladium and/or ruthenium. The catalytic metal component may be carried on the surface and/or in the mind of the carrier as mentioned above.
In this embodiment (2), the catalyst is preferably used in an amount, in terms of platinum group metal atoms, of 0.00001 to 0.1 mole, more preferably 0.00005 to 0.01 mole, per mole of 1,2-epoxy-5,9-cyclododecadiene.
The hydrogenation reaction of the embodiment may be carried out in the liquid reaction medium as mentioned above.
In still another embodiment (3) of the present invention, a starting material comprising at least one epoxidized C6-C12 cyclohydrocarbon compound, for example, an epoxy cycloalkane and/or an epoxy cycloalkene, is brought into contact with hydrogen in the presence of a catalyst comprising a catalytic platinum group metal component and a carrier comprising xcex1-alumina, under a hydrogen pressure of 0.1 to 5.4 MPa on gauge at a temperature of 100 to 280xc2x0 C., to produce cycloalkanone and a cycloalkanol.
In this embodiment (3), preferably the starting material comprises epoxycyclododecane, epoxycyclododecadiene and/or epoxycyclododecene, and the resultant product comprises cycododecanone and cyclododecanol.
In this embodiment (3), the catalytic metal component is carried on the surface and/or in the inside of the xcex1-alumina carrier. The catalytic metal component is preferably in the form of fine particles having an average particle size of 0.1 nm to 1000 nm.
The carrier of the catalyst for this embodiment comprises xcex1-alumina which has an xcex1-alumina crystalline structure confirmed by the X-ray diffraction pattern. The xcex1-alumina may contain several % by weight or less of impurities, for example, Na, Mg, Fe, SiO2 which may not affect the catalytic activity of the xcex1-alumina. Sometimes, an alkaline metal and/or an alkaline earth metal enhance the catalytic activity of the xcex1-alumina.
There is no limitation to the surface properties and fine pore properties of the xcex1-alumina carrier. Usually, the xcex1-alumina carrier preferably has a specific surface area of 20 m2/g or less, more preferably 1 to 20 to m2/g, and an average pore size of 50 to 500 xcexcm.
In the catalyst, the catalytic metal component is preferably in an amount of 0.1 to 20%, more preferably 0.5 to 10% by weight, based on the weight of the xcex1-alumina carrier. When the amount of the catalytic metal component is less than 0.1% by weight based on the xcex1-alumina carrier, the resultant catalyst may exhibit an insufficient catalytic activity. If the amount of the catalytic metal component is more than 20% by weight, the expensive platinum metal is employed with low efficiency.
The catalyst for the embodiment (3) may be in the form of fine particles or in the form of pellets. The fine particles preferably have an average particle size of 1 xcexcm to several hundreds xcexcm and are useful for liquid phase, catalyst-suspension bed type catalytic reaction. Also, the pellets of the catalyst preferably have a length of 1 to 10 mm and a diameter of 2 to 6 mm, and are useful for catalyst-fixed bed type catalytic reaction.
In the embodiment (3), the hydrogenation reaction of the epoxidized C6-C12 cyclohydrocarbon compounds may be carried out in the liquid reaction medium as mentioned above.
In the method of the present invention, the reaction time is variable in response to the reaction temperature, the hydrogen pressure, the type and amount of the catalyst and the concentrations of the starting material and hydrogen in the reaction system. Usually, the hydrogenation reaction is completed within about 0.1 to about 5 hours, particularly 1 to 3 hours.